The present invention relates to a magneto-optical head and, more particularly, to a magneto-optical head for magneto-optically reading information from a magneto-optical recording medium.
A conventional magneto-optical head requires first, second and third optical systems, as described in the Japanese Patent Disclosure No. 233,448/1986. The first optical system is provided for irradiating a laser beam to a magneto-optical recording medium. The second optical system for reading the information detects changes in polarization of a reflected or transmitted beam from the recording medium. The third optical system for obtaining servo error signals from the reflected or transmitted beam detects changes in a luminous energy of the reflected or transmitted beam. In this structure, the reflected or transmitted beam from the recording medium is divided into two beams by a beam splitter consisting of a half mirror or the like. One of the split beams is led to a polarization analysing device, such as a polarized beam splitter and a light detecting element in order to read the recorded information. The other is led to an optical device for detecting a focus error signal, a track error signal and the luminous energy of the reflected or transmitted beam, none of which is subjected to the change of the polarization.
The above-described conventional magneto-optical head has a disadvantage of a complex and massive structure, which makes it difficult to reduce the size and cost of the magneto-optical head on account of an individual arrangement of the second and third optical systems.